Vb link with fortran language is realized and solved successfully . both program interfaces are friendly and convenient to operate . the post - stall behavior of three specific compression systems is analyzed by the application of the post - stall behavior simulation programs developed in this paper 以三种特定的压缩系统为研究对象,展示了这两种过失速性能模拟技术的实用性和有效性,单级压缩系统的过失速状态的数值模拟结果得到了实验结果的很好支持。
The radial , circumferential and axial distributions of static pressure amplitude under post - stall conditions are measured and compared . the experimental results have proved the feasibility of using one - dimensional model to analyze the post - stall behavior and recoverability of compression systems . at the same time , the results of experiment have provided the first - hand data for analyzing and calculating vibrating response of blades under post - stall conditions 以单级轴流压气机实验器为对象,研制了两种型式的静压动态探针?梳形针和圆盘针,详细测量了过失速状态下流道中压力沿径向、周向和轴向分布,验证了用一维模型分析压气机过失速性能和失速可恢复性的可信度,同时为过失速状态下叶片的振动响应分析计算提供了第一手实验数据。
The main content of this thesis includes : ( 1 ) the introduction of theory of digitalization if receiver , including the theories on signal sampling , multi - velocity signal processing , pulse compress , and so on ; ( 2 ) design of system scheme based on system requirements , including confirm the sampling rate , design the decimation filters in digital down converter , and design the matching filters ; ( 3 ) analysis and discussion about the software and hardware implement schemes of digitalization if receiver and the pulse compression system , including the introduction and choice of chips , the realization of system module in fpga , design hardware circuit ; ( 4 ) presentation on the test results about our system based on fpga 本文的主要工作包括: ( 1 )介绍线性调频信号的数字中频接收的原理,主要包括信号采样理论,多速率信号处理理论,脉冲压缩理论等。 ( 2 )结合系统指标进行系统总体方案的设计和论证,包括采样率的确定,数字下变频各级抽取滤波的设计,以及匹配滤波的设计。 ( 3 )分析讨论并给出具有实用价值的线性调频脉冲雷达中频信号数字化接收及脉冲压缩处理系统的软硬件实现方案,包括芯片的选择和简介,系统各个模块在fpga中的实现,以及硬件电路的设计。
Then a pulse compression system based on frequency - domain means is presented . finally , after discussing time - frequency analysis theory in general , wigner - ville distribution for lfm signals are presented , the effect of matching filtering and doppler shift are demonstrated . the cross item appearing in the condition of multi - component is investigated also 最后在简要介绍了时频分析的基本概念后,采用wigner - ville分布对线性调频信号作了仿真分析,讨论了匹配滤波的过程和多普勒频移的影响,对多分量信号时出现的交叉项问题作了探讨。
Furthermore , the one - dimensional unsteady stage - by - stage model program is extended to study the recoverability of compression systems . the recoverability of three specific compression systems and some influence factors of recoverability are analyzed to make use of the program developed in this paper . they are verified for some experiment results on hand 本文进一步发展了一维非定常单元容积模型的应用分析范围,以三种特定的压缩系统为研究对象,研究了压缩系统的失速可恢复性及其影响因素,取得了已有实验结果的证实。
In this dissertation the pulse compression performances of linear frequency modulation signals ( lfm ) , nonlinear frequency modulation signals ( nlfm ) and design of their side - lobes suppression filters are analyzed , and design of the pulse compression program of 4 pieces of adsp21160 in the processing unit and the program of single piece of adsp21160 and fpga in the interface unit of the pulse compression system are introduced in detail 全文分析了线性调频信号( lfm ) ,非线性调频信号( nlfm )的频域脉冲压缩方法及其旁瓣抑制滤波器的设计和优化,详细介绍了脉冲压缩系统中基于4片adsp21160的处理单元和单片adsp21160和fpga组成的接口单元的软件设计。
The collection and compression system of ecg signal is one small - scale ecg administrative system . the characteristic with high - fidelity , high dependability of ecg signal gathered , can store and show through the computer , for the doctor to monitor real - timly , and pay close attention to the patient ' s health in time , in order to prevent and treat effectively 心电信号的采集及压缩系统是一个小型的心电管理系统,采集的心电信号具有高保真、高可靠性的特点,可以通过计算机存贮和显示,供医生实时地进行监测,及时关注患者的身体状况,以便进行有效地预防和治疗。
The validation of the programs is verified by the good agreement between the simulation results and experimental results in the single - stage compression system . it is also verified that only a qualitative analysis can be obtained using the one - dimensional unsteady lumped model ; but the one - dimensional unsteady stageby - stage model is more suitable for actual compressor operating conditions and can serve as an effective analytic tool for studying the post - stall behavior and improving recoverability of compression systems 判明了一维非定常总体模型只能定性的分析压缩系统的过失速性能,在定量的分析上存在着一定的局限性;而一维非定常单元容积模型更能反映压缩系统实际情况,从而为研究压缩系统的过失速性能和改善压缩系统的失速可恢复性提供了有力的工具。
Simulation results show that the surge line moved up - left relative to the original one and surge margin became larger when wet compression is used , which means wet compression can extend steady - operation regions of compressors and the si a - 02 gas turbine . at last , based on the moore - greitzer model surge and rotating stall of a compression system with wet compression is modeled with consideration of inlet evaporative cooling and compressor pressure rise when wet compression is used 哈尔滨工程大学博士学位论文最后,本文在压缩系统moors grei上zer模型的基础上,考虑进口蒸发冷却的作用和压气机湿压缩过程的作用,推导出了湿压缩系统喘振和旋转失速的统一模型,该模型可以模拟系统发生喘振和旋转失速时的瞬态响应以及喷水湿压缩对系统瞬态响应的影响。
In the wavelet image compression system , the choice of wavelet basis directly determines the statistical characteristics of wavelet coefficients , thus it not only affects subsequent processes , but also affects the final compression ratio and the the quality of reconstructed image . the method of realizing wavelet transform determines computational complexity , whether the transformed data can be lossless recovered or not , etc . , accordingly it can affect the time spending on compression and the quality of reconstructed image 在小波变换图像压缩方法中,小波基选择的好坏,直接决定小波系数的性质,从而影响压缩过程中后继的其它处理,影响最终的压缩比和图像重建质量;小波变换的实现方法决定着计算的复杂度、数据的恢复性能等,从而影响压缩时间和图像重建质量。